Circumscribed palmar or plantar hypokeratosis: two cases of a recently described entity of unknown origin

Circumscribed palmar or plantar hypokeratosis is a new entity recently described by Perez et al in 2002. It seems to be underdiagnosed or clinically it is often misdiagnosed as Bowen's disease or porokeratosis. Obviously the number of case reports of circumscribed palmar or plantar hypokeratosis has increased since the first publication by Perez et al.The histopathological hallmarks of this condition are a stair-like configuration with an abrupt thinning of the stratum corneum from uninvolved to involved skin with a central hypokeratotic area. There are no atypical keratinocytes or cornoid lamellation. We describe two new patients with circumscribed palmar hypokeratosis. In one case there were additional histopathological features including the loss of granular cell layer in the center of the lesion and an overlying compact thin parakeratotic layer.